Portable circular saws are tools which are commonly used in the construction industry for building and remodeling purposes. The tools are used both for factory and on-site construction. The circular saw is an extremely efficient tool for cutting many different types of materials including such obvious ones as wood, plastic laminates, stone, masonry and the like.
One problem which is associated with tools of this type concerns the debris which accompanies a sawing operation. Commercially available circular saws typically rotate the cutting blade at speeds ranging from 4000 to 6000 revolutions per minute. This high speed operation of the cutting blade causes the sawdust and other particles resulting from the cut to be expelled into the surrounding air thus creating a hazard to the operator and causing the building location to become filled with dust particles. Certain types of cutting operations also require the introduction of cooling fluid, such as water, onto the cutting blade, and this fluid is also expelled into the atmosphere further contaminating the building site. When the cutting operation is being performed as part of a remodeling operation in a home, office building, hospital or the like, a major problem arises with respect to the attempt to confine the cutting debris and to subsequently clean up the building site. This can be a very costly procedure.
Conventional saws employ guards to protect the operator from contact with the cutting blade. These guards normally take the form of a stationary upper guard and a lower movable guard which is capable of covering the lower portion of the cutting blade and which can be swung or rotated out of the way during a cutting operation. These guards are wholly ineffective in controlling the confinement of dust or water during a cutting operation. Attempts have been made to combine a suction removal hose with a conventional guard, such as in U.S. Pat. No. 3,882,598, but such arrangements provide only slight improvement over conventional circular saws. Other attempts have been suggested whereby telescoping blade guards have been combined with suction sources in an attempt to remove dust during a cutting operation, but these efforts have not resulted in a suitable acceptable cutting tool. An example of such efforts can be seen in U.S. Pat. No. 3,034,493.